Slow break switch



'April 28, 1936. N. c. SCHELLENGER SLOW BREAK SWITCH Filed MaICh 6,19.55

2 sheets-sheet 1 llllllllllll Il s. wmf MMM# Q C 5 n MM w. N W/ April28, 1936 N. c. scHl-:LLENGER 2,039,117

SLOW BREAK SWITCH Filed March 6, 1933 2 Sheets-Sheerl 2 Patented Apr.28, 1936.` n l UNITED STATES PATENT OFFICE SLOW BREAK SWITCH Newton C.Schellenger, Elkhart, Ind., assignor to Chicago Telephone Supply Co.,Elkhart, Ind., a corporation of Indiana Application March 6, 1933,Serial No. 659,708

.8 Claims. .(Cl. 20o-'164) My invention relates to opening and closingnism which may be readily incorporated with of electrical circuits andapplies particularly to and be actuated by a common positive actuating aslow-break switch. shaft ofv a rheostat. Heretofore, switches have beenemployed which A further object is to provide a low sounding arerelatively large in sizev for a given current signal, as a click, toinform the operator when and voltage rating and wherein the cost ofmanuthe circuit is opened or when closed'. facturing and assembly areIrelatively high; so Another object is the switch may be provided the useof such switches as aforementioned is with an electrostatic shield thateffectively preundesirable in places where space is at a premvents humpick-up by the volume control from ium and quality is demanded at a lowcost. live parts of the switch. t l0 In the use of slow-break switchesthe arcing Another object is to construct a switch Wherewhich occurswhen the circuit .is broken and/or in the contact surfaces may engagewith a wipcompleted tends to pit the contact terminals ing action. whicheventuates into high resistance contacts Another object is to embodycontactors in a Cil and, also, reaches the stage where a continualswitch of such area that suitable heat dissipa- 16 arc occurs toentirely destroy th contact tertion is readily eiected. minals. If anarc in such simple structural de- Another object is to have the contactinitially vices could be taken by one set of related contact made at onepart of each jaw and the continuous jaws and a second set of contacts becontinually circuit at another part of the jaw. clean and smooth, thelife of the switch would be With the above objects in view my inventionis 20 materially increased and the contact resistance embodied in aswitch having a casing, a unitary continually low, stationary terminalcomprised 'generally oi a -A more satisfactory manner of keeping thesoldering lug, a holding structure and a plurality contact jaws cleanand insuring longevity to meet of contact jaw members; and a resilientengaging Aall conditions is to utilize two Isets of jaws formed movableterminal comprised of a soldering lug, 25 to meet as dihedral angles.With such a conholding structure, and a plurality of contact jawstruction one pair of meeting members will conmembers; the jaw membersof each terminal potinually arc so the tip of the movable membersitioned not only to open and close the electrical will wear away. Afterthe switch has operated circuit but to react with a vburnishing orsufficiently to eat a portion of the tip of one jaw, a wiping action inorder that the jaws be 30 then the other jaw breaks the current so as tokept clean; a switch operating arm adapted to draw the arc. Meanwhile,the contact surfaces oscillate the resilient terminal contact jaw memofboth sets of jaws are kept smooth and clean bers and the operating armengageable at a prebecause of `the wiping action. The arc whichdetermined position by a suitable resistance adstarted at one set ofjaws, then moved to the justing arm of an adjoining rheostat. 35

second set of jaws, will now move back to the My invention hasparticular application in radio rst set of jaws, thus causing analternate arcing, sets for automobiles where space is at a premium. atlong intervals, to continue until the contacts As heretofore employed,the switch is mounted are completely pitted away; however, there is theupon the back base of the rheostat with valuable 40 assurance of goodlow resistance contacts durspace above and below the switch beingunoccu- 40 ing the intervening-period of Operation. As the pied, whereasif the switch is mounted within the are and its detrimentaleifect-pitting-is Small, extended transverse planes of the bases of thethe switch will operate for a long period. rheostat casing diametricailyopposed to the rheo- It is, therefore, an object 0f my invention to statterminals, space adjacent the lateral surface 15 construct a switchwhich may have its mechanof the cylindrical rheostat casing whichotherwise 45 ical parts inserted within the casing and then would not heoccupied, is then filled,

have the parts locked therein when the switch Furthermore, it is of theutmost importance to iS placed in Operative DOSOII. construct the partsof the switch mechanism so A further object of my invention is toconstruct they may be readily assembled in their proper a switch whichhas a positive circuit opening positionin manufacturing quantities. 5omeans and a resilient inherent closing means. other objects of thisinvention are to provide A further Object iS t0 Utilize a plurality 0fC011- an improved device of the character described, tact Surfaces, 011e0f which rflWayS takes the that is easily and economically produced,sturdy arc. in construction and having a maximum efficiency Anotherobject is to provide a switch mechaand accuracy. 55

With these and related objects in view, my invention consists in thefollowing details of construction and combination of parts, as will bemore fully understood from the following specification, taken incommotion with the accompanying drawings, in which:

Figure 1 is a fragmentary sectional view of my invention combined with arheostat;

Figure 2 is an end view looking in on the switch Per Se;

Figure 3 is a side elevational view of my invention looking into theswitch mechanism chamber;

Figure 4 is a sectional view taken on the line 4-4 of Figure 1;

Figure 5 is a perspective view of a xed terminal, which when takentogether with Figs. 6, 7, 8 and9 gives an exploded view of the switchmechanism;

Figure 6 is a perspective view of the resilient terminal;

Figure 7 is a perspective view of an insulated block adjoining theresilient terminal;

Figure 8 is a perspective view of the terminal actuating element;

Figure 9 is a perspective view oi' the insulated block upon which theresilient terminal rests;

Figure 10 is an exaggerated view, taken on the line IIi--I of Figure 4,wherein the contact jaws iirst are engaging;

Figure 1l is a view similar to Fig. 10 wherein the contact jaws are incomplete engagement; and

Figure 12 is a fragmentary sectional view taken on the line of |2-i2 ofFig. 4.

The particular switch herein described is of a type which findsconsiderable use in radio receiving sets. It is adapted to be mounted onthe side of a rheostat, potentiometer or similar volume or tone controldevices by means of clamps or other suitable fastening means.

The switch in the preferred embodiment is actuated by a suitable pin,lobe or protrusion mounted on the rotating, or even a translatory,contact arm of the volume or tone control unit.

The body or casing, generally designated A, of the switch is made ofmoulded insulating material having suitable recesses therein. A phenolcondensation"product is particularly suitable.

'I'he mechanism of the switch consists of a fixed terminal, generallydesignated B, and forming the engaged element of the switch; a resilientterminal, generally designated C, constituting the movable engagingelement for the switch and the positive actuating member, generalydesignated D.

Referring now in detail to the drawings, the combined rheostat andswitch unit is generally shown in Fig. 1. This unit comprises the casingor housing which contains the rheostat, generally designated E, and thecasing or housing A which contains the switch for controlling the powercircuit to which the unit is connected. The rheostat E is containedwithin a cylindrical cup shaped shell member F completely enclosed anddust proof. The shell F has a cylindrical wall l enclosed between fiatbases. The two housings are held in cooperative relationship by means ofpressed out ears 2 and 3 of the cylindrical rheostat wail I whichcooperate with raised lugs 4 and 5 formed on the ceiling 6 and floor 'lof the structure and a contact member, hereinafter described in detail.'I'he soldering lug 'orw arcuate end IIJ of the terminal B has anaperture i2 therethrough to which suitable flexible lead-wires may beattached in any manner well known to the art. The holding structure andthe contact member; connected to the soldering lug, have a median,longitudinally positioned, strengthening and holding rib i4therethrough. The soldering lug i0 merges into a wider holding structureor retaining portion i6 (see Fig. 5) having flanges i8 and 20 bentdownwardly; the flanges oi' the widened or broadened structure I6,areadapted to engage a front wall 22, and sides of grooves 23 and 24, inthe upper extremity of side walls 25 and 26, respectively, of the casing(see Figs. 1, 2, 3 and 4), whereby turning of the terminal as well aslateral movement is prevented. The holding structure i 6 is connected toa contact jaw supporting member 26 by a bight section 30.

The contact member or contact jaw supporting member 28 has angularlyprojecting resilient arms 32 and 34, which in turn have projectingdownwardly therefrom (slightly less than see Fig. 10), resilient flatplanar contact jaws 36 and 38, respectively. The contact jaws 36 and 38are anguiariy displaced relative to the transverse and longitudinal axesof the terminal B. A triangulariy shaped end 40, of the terminal Bhaving an apex attached to the supporting member 23, acts as an abuttingmember to engage an insulating strip 4| against the casing I of therheostat, generally designated F; and as the ears I8 and 2li of the sameterminal B abut against the chamber front wall 26, any longitudinaldisplacement of that terminal is prevented.

'The integral resilient terminal C is comprised of a soldering lug, aholding base structure and a resilient contact member which oscillatesto open or close the circuit, hereinafter described in greater detail.The oscillating arm 42 of terminal C has two angularly disposedelongated contacting jaws 44 and 46, which are adapted to wipe andcontact its respective complemental jaws 36 and 38, on the engagedterminal B. The jaws 44 and 36, and 46 and 38 are so disposed as to forma dihedral angle which is instrumental in effecting the burnishing ashereinafter further described. Spaced a short distance from the end is apressed out tongue 45 which passes through a suitably alined aperture 50of an adjoining insulating strip or shield 52. The oscilating arm widensas it approaches a holding member base 53; which is of sufficient widthto easily slide within side wall grooves 54 and 55 out into the lowerextremity of the side walls 25 and 26.

The base 53 narrows sharply at its junction vwith the soldering lug 56,so that two short shoulders 58 and 60 are formed therein, which areadapted to engage the vertical side walls and front wall of the casingchamber grooves 54 and 55, whereby movement of the base to the left (asviewed in Fig. 1) is limited and a tongue 62 stamped downwardly from thebase prevents movement to the right (as viewed in Fig. l) when theinsulating strip 52 is held rigid, thus longitudinal or transversemovement of the base, as well as twisting, is prevented. The downwardlyprojecting stamped out tongue 62` having the iowermost edge extending tothe right (Fig. 1) is adapted to engage a portion of an edge 64 inanotched section 66 of an insulating strip 68. The soldering lug 56 hasan aperture 69 therein to which suitable flexible lead wire or wiresmaybevreadlily attached, as is well known in the art. A ridge 1| in thesolderinglug is adapted to close an alined opening 13 in the front wall22, so no dust, dirt, solder or soldering flux may enter the switchchamber 15.

The positive actuating member D, for transmitting motion from therheostat mechanism to the oscillatory switch arm has a substantiallyrectangular base 10 which rests on the surface of the insulating strip68, the base side edges being located in contact with side walls ofgrooves 54 and 55. An integral vertical tapered resilient oscillatoryarm 12, attached to the base, diverges from the vertical plane of theinsulating strip 52 as its end is approached toform a lobe 14 and thenreverses itself as indicated at 16 to form a substantial U-shapedsection. The ends of the U-shaped section lie in the sameA plane andengage a face of the insulating strip 52, which strip in turn has itsopposite face or surface against the oscillating contact arm 42.

Attached to the base 18, as an integral part thereof, is an off-set arm82 connected to the base 10 by the bend 84. The base 10 sits upon 'inthe section 92.

with the snapping of lobe 14 into section 92 the lobe 88 will snapagainst the stop member or the upper surface of the insulating strip 68as the bend 84 engages an edge 86 of the strip and the arm 82 partiallyencloses the bottom of the strip.

A lobed surface 88, (see Fig. l) on the rheostat rotatable arm member 90coacts with the lobe 14 of the actuating member D to break the circuitwhen engagement occurs and to close the circuit when disengaged. Anotched or depressed section 92 on the rheostat rotatable member at theextremity of the lobe 88 cooperates with lobe 14 of the actuating memberD to eiIect a nesting or anchoring thereof within said section.

When they circuit is closed and it is desirable to open the circuit,movement of the shaft causes the lobe 88 of arm member 80 to engage thelobe 14; further movement oscillates arm 12 whereby its end 16 (see Fig.8) is forced against the insulating member 52. Member 52 in turn isforced against the contact arm 42 which is oscillated to break thecircuit. When the lobe 88 passes over lobe 14 the latter snaps intonotched section 92 thereby anchoring or engaging lobe 14 Substantiallysimultaneously tongue 9, producing by this snap action an audible c1ick.

v It is to be noted that the resilient contact arm 42 may have a slighttwist therein so that one of the contact jaws thereon will be in advanceof the other contact jaw. By such arrangement the arc will be made bythat particular jaw when the' circuit is completed, and, as is obviousthe arc is also taken by the same jaw when the circuit is broken. Thus,the second coacting pair of jaws is clean and free of any pit marks sothe contact resistance is practically constant for the switch whichinsures long life for carrying heavy-currents at relatively highvoltages.`

,surfaces thereby occurs.

As the arrangement of jaws is symmetrical, but one set of complementa]jaws 36 and 44 will .be described. The tip 44C of the jaw 44, rst

approaching the stationary contact 86, draws the pletes the wipingaction.

arc (Fig. 10) forming a diherdral angle X. As

the jaw 44 finally sweeps into place against the' jaw 36, as shown inFig. 11, the dihedral angle X is closed, the jaw 44 as it sweeps alongcom- Upon breaking the contact, the above wiping action likewise occursin the order of Figs. 11 and 10.

After the switch has operated suiliciently to eat a portion of the tipof one jaw, the arcing will then move to the second set of jaws, untilthe tip of one jaw of that set is obliterated to a greater extent thanthe first mentioned jaw. Meanwhile, the contact surfaces of both sets ofjaws are kept smooth and clean because of the wiping action. The arcwhich started at one set of jaws, then moved to the second set of jaws,will upon further usage move back to the first set of jaws, thus causingalternate sets of jaws t0 arc, until eventually the contacts arecompletely obliterated; however, there is the assurance of good lowresistance contacts during the long intervening period oi' operation.

Assembly The various elements are constructed to provide exact, rapidcommercial methods of assembly. The casing A has side walls 28 and 28,the front wall 22, and top and bottom walls 8 and 1 forming the chamber1l wherein the switch mechanism is installed. An entrance or opening tothe chamber 18 fits adjacent the window 8 in the casing of the rheostatand the casing is held rigidly to the rheostat as hereinbeforedescribed.

With the rib I4 depressed downwardly from the upper wall and the ears I8and 28 resting in the grooves 28 and 24 in the side walls of thechamber, upon assembly the resilient terminal C is inserted in the aimedopening 18 with the positive actuating member D but with the insulatingstrips I2 and 88 interposed properly between the terminal C and member Dand the entire unit is then pressed into the chamber so the solderinglug 58 will project through'the alined opening 18 in the side wall ofthe casing.

The fixed terminal B is then inserted in an alined terminal opening 84with the upper surfaces of the holding section |8 and the supporting jawmembers 28 against the ceiling of the chamber 15. The ears 2 and 8 ofthe rheostat easing are then clamped over the raised lugs 4 and 5,respectively, of the switch casing. The

tongue 8 is engaged by one side of the lobe 88 of the arm when the lobe88 moves clockwise (see Fig. l) for breaking the circuit, and by theledge 96, when'the arm 98 moves counterciockwise, to the limit of itspath.`

A shoe 88 driven by the rheostat arm 90 engages a suitable resistor 88of the rheostat. The corelation of the lobe 88 and the contact shoe ofthe resistor is such that but a slight movement of the shoe over theresistor opens or closes the switch andthe resistor terminals |88, |02and |84 are located on the rim of the casing dametrlcally opposite thelocation of the switch casing. It is thus seen that a substantial flatrectangular shaped combined. rheostat and switch is thus embodied whichwhen inserted on a radio panel will occupy but a minimum volume incomparison with the former structure as employed in the art.

It is to be noted that the stationary jaws may be flexible and themovable jaws more rigid to eilect the same result and operation.

The rheostat arm 8l moves but a small arcuate distance to open or closethe'switch whereby prac tically the entire length of the resistance iseffectually to be utilized for its particular function.

Lugs |08 and |08 (Fig. 2), mounted centrally upon the circular segmentalportion of the walls 25 and 26, respectively, or molded integrally withthe switch casing A, protrude through suitable alined openings in theinsulating strip 4l, the rheostat casing I and the rheostat lining (seeFig. 12) for the purposes of providing' definite, predetermined aliningrelationship of the rheostat and the switch; for providing extrasupports for the switch casing when positioned on the rheostat casing;and to prevent turning of the casings with respect to one another.

Although the invention has been described in considerable detail, suchdescription is intended as illustrative rather than limiting, as theinvention may be variously embodied, and the scope of the invention isto be determined as claimed.

l. In combination with a switch, a casing comterminal having a holdingportion thereof adapted to be retained within the top grooves of theside wall and the ceiling of said chamber, a resilient oscillatoryterminal having a base, contact portions and a resilient member thereon,a positive actuating arm having a base and adapted to oscillate saidresilient member, a plurality of insulating members separating thepositive actuating means and the resilient terminal, said resilientterminal base and positive actuating means base adapted to be heldwithin the grooves in the side wall adjacent the floor of said chamberto prevent lateral movement and twisting.

2. In combination with a switch having a grooved casing, a unitarystationary element comprising a soldering lug, a plurality of anges toengage side walls of said grooves whereby side motion and rotation isprevented, a plurality of angularly disposed contact portions and anabutment member connected to the body of said terminal, alongitudinally'extending rib in said terminal, a second terminal havinga plurality of portions to engage the contact portions of said rstterminal whereby an electrical circuit may be completed.

3. In combination with a switch, a ilxed terminal having a solderinglug, a holding portion and a plurality of contact portions on said xedterminal, a holding base, a resilient arm on saidl base and a pluralityof contact portions formed on said resilient arm, said sets of contactportions positioned to coact with each other to form a dihedral anglebetween contacting surfaces.

4. In combination with a switch, a casing comprising a housing having anopen face, a plurality of grooves formed in the interior of the housingand extending to the open face, a stationary terminal having a holdingportion thereof retained within certain of said grooves, a resilientoscillatory terminal having a base secured in grooves spaced from thestationary terminal, and a positive actuating arm having base and armportions, the base portion being secured in certain of said grooves.

5. In combination with a switch, a casing comprising a housing having anopen face, a plurality of grooves formed in the interior of the housingand extending to the open face, a stationary terminal having a holdingportion thereof retained within certain of said grooves, a resilientoscillatory terminal having a base secured in grooves spaced from thestationary terminal. a positive actuating arm having base and armportions, the base portion being secured in the same stationary elementcomprising a soldering lug extending from the casing, a plurality oflateral flanges engaged in the casing grooves, a plurality of spacedcontact portions, and an extended abutment portion, 4the oscillatoryterminal comprising a. soldering lug, a base portion and a resilientportion carrying contact portions to coact with the contact portions ofthe stationary element.

7. In combination with an internally grooved casing, a switch structurecomprising a unitary stationary terminal element and a unitaryoscillatory terminal element, said elements being retained in spacedgrooves in the casing, the stationary element comprising a soldering lugextending from the casing, a plurality of lateral flanges engaged in thecasing grooves, a plurality of spaced contact portions, and an extendedabutment portion, the oscillatory terminal comprising a soldering lug, abase portion and a resilient portion carrying contact portions to coactwith the contact portions of the stationary element, and an actuatingmember having a securing arm iitted in the grooves with the base portionof the oscillatory terminal and an actuating arm adjacent the resilientportion of the oscillatory member.

8. In combination with an internally grooved casing, a switch structurecomprising a unitary stationary terminal element and a unitaryoscillatory terminal element, said elements being retained in spacedgrooves in the casing, the stationary element comprising a soldering lugextending from the casing, a plurality of lateral flanges engaged in thecasing grooves, a plurality of spaced contact portions and an extendedabutment portion, the oscillatory terminal comprising a soldering lug, abase portion and a resilient portion carrying contact portions to coactwith the contact portions of the stationary element, an actuating memberhaving a securing arm fitted in the grooves with the base portion of theoscillatory terminal and an actuating arm adjacent lthe resilientportion of the oscillatory member, insulating means fitted in thegrooves between the actuating .member and oscillatory member, and .aninsulating member extending between the actuating arm and the resilientportion of the oscillatory member.

NEWTON C. SCHELLENGER..

CII

